1. Field of the Invention
The present invention relates to a route planning method of a navigation system, and in particular relates to a substitute route pre-planning method of a navigation system.
2. Description of the Related Art
Global positioning system, abbreviated GPS, is a navigation system that integrates satellite and wireless technologies to provide a user's precise location, speed and local time. GPS is used extensively, and many GPS technologies and business opportunities are developed rapidly as satellite technologies advance. At early stage, GPS was intended only for military units and used for military purposes such as the precision positioning of fighters, ships, motor vehicles, ground personnel and targets. Currently, GPS is free for civilian use and can be used in the positioning, and in technologies such as integrating space satellites and communication technology which is developed rapidly. For example, GPS can provide accurate information such as the speed, direction and distance of a moving vehicle. This enables emergency vehicles such as ambulances to accomplish life-saving mission more effectively. The driver of the vehicle can maintain constant awareness of their current position and obtain route information to a target destination using an electronic map.
The present portable navigation device mainly comprises a touch screen and function keys around the touch screen. The touch screen mainly shows the function menu, input interface and 2D/3D navigation mode. The user selects the function shown on the screen by pressing the function key or directly touching the screen or via voice control. Furthermore, the user can input the starting point and the destination via hand writing and the GPS then navigates according to the start point and the destination.